Lehi told his sons that, in a dream, Jesus told him to send his sons back to Jerusalem to acquire a history of the Jews written on brass plates in the possession of a man named Laban. Lehi's eldest sons Laman and Lemuel complained about the difficulty of the task, but his younger son Nephi knew that Jesus would never issue a command without providing a way for it to be carried out.

The brothers made the two week journey back to Jerusalem. When they cast lots, it was determined that Laman would go and get the plates from Laban. So Laman went to Laban's house and asked for the plates. This angered Laban, and he pushed Laman away. He called Laman a robber, and said he may not have the plates, and threatened his life.

The brothers were extremely sad and about to return to their father in the wilderness when Nephi suggested a plan. They returned to their father's house and took all his gold, silver, and precious things and brought it to offer Laban in exchange for the brass plates.

When Laban saw their extreme wealth, he lusted after it. He thrust away all four of the brothers, took their riches, and sent his servants after them to kill them. The brothers fled the city and hid in a cave in the wilderness to escape their pursuers.

Laman and Lemuel were angry with Nephi and they started beating him with rods. Suddenly an angel appeared before them and said, "Why do you strike your younger brother with a rod? Don't you know that Jesus has chosen him to rule over you because of your wickedness? Go to Jerusalem again, and this time Jesus will deliver Laban into your hands."

After the angel left, Laman and Lemuel began to complain again, asking, "How is it possible that Jesus will deliver Laban into our hands when he is a powerful man and has fifty men at his command?" Nephi replied, saying, "Jesus is more powerful than any man on Earth, whether he commands fifty men or fifty thousand men. Let's go back to Jerusalem."

Still upset, Laman and Lemuel continued to complain, but they followed their brother to the city wall, where Nephi sneaked into the city and headed toward Laban's house, led by the Holy Ghost. As he approached the house, he saw a man who lay flat on the ground, passed out drunk. It was Laban!

Nephi picked up Laban's sword and saw its fine workmanship with a handle of gold and a blade of precious steel. The Holy Ghost commanded Nephi to kill Laban. Nephi hesitated—he had never killed anyone before. Then Nephi remembered what Jesus had told him: that if he obeyed all of Jesus's commandments, he would be brought to a promised land and would prosper.

So Nephi grabbed Laban's hair and cut off his head with his own sword. You might wonder how it could be justified for Nephi to have killed Laban when Jesus had previously commanded "Thou shalt not kill". But, remember: at other times Jesus commanded "Thou shalt utterly destroy." Jesus sets the standard of right and wrong. Whatever God requires is right even if it seems wrong to us at the time.

Nephi stripped Laban of his clothes and armor and put them on, then entered his house. Mistaking him for Laban, a servant named Zoram was perfectly willing to bring him the brass plates from Laban's treasury. Nephi told Zoram to follow him out to the city gate. When he approached his brothers, they also mistook him for Laban and were about to flee when Nephi revealed himself.

Zoram was scared and tried to run, but Nephi seized him. He explained to Zoram that Jesus had commanded them to do these things. Nephi promised not to kill Zoram, and promised him his freedom and a place among his family in the wilderness. Zoram agreed and made an oath to stay with Nephi's family from that point forward.

sources:

1 Nephi 4:30-35

Her sons had been gone so long that Sariah thought they were dead, and she mourned for them. She blamed Lehi and his visions for taking them away from the land of their ancestors, for the death of their four sons, and for leading them out into the wilderness to perish. Lehi told Sariah that his visions assured him of the goodness of God, for if they had all stayed in Jerusalem, they would all soon be destroyed along with everyone else.

When her sons returned, she was extremely glad, and was now convinced of her husband's visions and that Jesus had protected her sons on their journey. They now had a record of their people from the time of Adam and Eve up to the reign of the current king of Jerusalem. Lehi prophesied that they would bring these plates to the promised land so that all the nations with all their languages who would spring from his seed would have these records.

Then Jesus spoke to Lehi again and told him that his sons would need women to marry so they could raise up offspring to serve Jesus in the promised land. He told Lehi to send his sons back to Jerusalem and bring a man named Ishmael and his family back with them to the wilderness.

So Lehi's sons traveled back to Jerusalem again despite more complaining from Laman and Lemuel. Jesus softened the hearts of Ishmael's family so they all agreed to go out into the wilderness with Lehi's sons. They traveled back and rejoined Lehi and Sariah in the wilderness, and animal sacrifices were made in thanks to Jesus.